The Bunker Buster Bomb is based on the GBU-28 developed in less than 8 weeks during Operation Desert Storm. They took several 8" artillery barrels and truned them into 4,000-pound LGBs. The first ones were delivered by an F-111F on a hardened communications bunker in Baghdad. One bomb destroyed it. One was used during Operation Iraqi Freedom. The system is still in use and has been supplied to Israel and South Korea.